Illusions are thought to make trouble for the intuition that perceptual experience is "open" to the world. Some have suggested, in response to the this trouble, that illusions differ from veridical experience in the degree to which their character is determined by their engagement with the world. An understanding of the psychology of perception reveals that this is not the case: veridical and falsidical perceptions engage the world in the same way and to the same extent. While some contemporary vision (...) scientists propose to draw the distinction between veridical experience and illusion in terms of the satisfaction or non-satisfaction of “hidden assumptions” deployed in the course of normal perceptual inference, I argue for a different approach. I contend that there are, in a sense, no illusions – illusions are as “open” as veridical experiences. Percepts lack the kinds of intentional content that would be needed for perceptual misrepresntation. My view gives a satisfying solution to a philosophical problem for disjunctivism about the good case/bad case distinction: with respect to illusions, every "bad case" of seeing an X can be equally well construed as a "good case" of seeing some Y (different from X). -/- . (shrink)

Ordinary people tend to be realists regarding perceptual experience, that is, they take perceiving the environment as a direct, unmediated, straightforward access to a mindindependent reality. Not so for (ordinary) philosophers. The empiricist influence on the philosophy of perception, in analytic philosophy at least, made the problem of perception synonymous with the view that realism is untenable. Admitting the problem (and trying to offer a view on it) is tantamount to rejecting ordinary people’s implicit realist assumptions as naive. So what (...) exactly is the problem? We can approach it via one of the central arguments against realism – the argument from hallucination. The argument is intended as a proof that in ordinary, veridical cases of perception, perceivers do not have an unmediated perceptual access to the world. There are many versions of it; I propose the following1: 1. Hallucinations that are subjectively indistinguishable from veridical perceptions are possible. 2. If two subjective states are indistinguishable, then they have a common nature. 3. The contents of hallucinations are mental images, not concrete external objects. 4. Therefore, the contents of veridical perceptions are mental images rather than concrete external objects. The key move is, I believe, from the fact that hallucinations that are subjectively indistinguishable from cases of veridical perception are possible to an alleged common element, factor, or nature, in the form of a mental state, in the two cases – that is, premise 2. Disjunctivism, at its core, can be taken as simply denying this move, and arguing that all that follows from the premise stating the possibility of hallucinations that are subjectively indistinguishable from cases veridical perception is that there is a broader category, that of “experience as of...”, which encompasses both cases.. (shrink)

We can learn much about perceptual experience by thinking about how it can mislead us. In this paper, I explore whether, and how, olfactory experience can mislead. I argue that, in the case of olfactory experience, the traditional distinction between illusion and hallucination does not apply. Integral to the traditional distinction is a notion of ‘object-failure’—the failure of an experience to present objects accurately. I argue that there are no such presented objects in olfactory experience. As a result, olfactory experience (...) can only mislead by means of a kind of property hallucination. The implications of my arguments are twofold. First, we see that accounts of representational content cannot always be based on the visual model. And, secondly, we see that we must recast the notion of nonveridicality, allowing for a notion of non-veridical experience that is disengaged from any particular object. (shrink)

Introduction MAX BLACK Nothing of any value can be said on method except through examples; but now, at the end of our course, we may collect certain general ...

The question how to account for illusion has had a prominent role in shaping theories of perception throughout the history of philosophy. Prevailing philosophical wisdom today has it that phenomena of illusion force us to choose between the following two options. First, reject altogether the early modern empiricist idea that the core subjective character of perceptual experience is to be given simply by citing the object presented in that experience. Instead we must characterize perceptual experience entirely in terms of its (...) representational content. Second, retain the early modern idea that the core subjective character of experience is simply constituted by the identity of its direct objects, but admit that these must be mind-dependent entities, distinct from the mind-independent physical objects we all know and love. I argue here that the early modern empiricists had an indispensable insight. The idea that the core subjective character of perceptual experience is to be given simply by citing the object presented in that experience is more fundamental than any appeal to perceptual content, and can account for illusion, and indeed hallucination, without resorting to the problematic postulation of any such mind-dependent objects. (shrink)

Despite the recent surge in research on, and interest in, synesthesia, the mechanism underlying this condition is still unknown. Feedforward mechanisms involving overlapping receptive fields of sensory neurons as well as feedback mechanisms involving a lack of signal disinhibition have been proposed. Here I show that a broad range of studies of developmental synesthesia indicate that the mechanism underlying the phenomenon may involve reinstatement of brain activity in different sensory or cognitive streams in a way that is similar to what (...) happens during memory retrieval of semantically associated items. In the paper’s final sections I look at the relevance of synesthesia research, given the memory model, to our understanding of multisensory perception and common mapping patterns. (shrink)

This contribution explores the psychological basis of illusion and the feeling of what is real in relation to a process theory (microgenesis) of mind/brain states. The varieties of illusion and the alterations in the feeling of realness are illustrated in cases of clinical pathology, as well as in everyday life. The basis of illusion does not rest in a comparison of appearance to reality nor in the relation of image to object, since these are antecedent and consequent phases in the (...) same mental state. The study of pathological illusions and hallucinations shows that the feeling of realness in an object depends on its coherence within and across perceptual modalities. Illusion is shown to be not the taking of the phenomenal for the real, but the overlooking of the real in the phenomenal, since all things exist, i.e. are real, as categories of intrinsic relations in the unique mode of their conception. Finally, the implications of the account are discussed in relation to moral conduct, self-realization, acceptance, and the will to enjoy a world of 'brain-born' mental phenomena. (shrink)

The 'content view', in slogan form, is 'Perceptual experiences have representational content'. I explain why the content view should be reformulated to remove any reference to 'experiences'. I then argue, against Bill Brewer, Charles Travis and others, that the content view is true. One corollary of the discussion is that the content of perception is relatively thin (confined, in the visual case, to roughly the output of 'mid-level' vision). Finally, I argue (briefly) that the opponents of the content view are (...) partially vindicated, because perceptual error is due to false belief. (shrink)

Recent work on seeing-in has taken a pluralist turn. There is variety among pictures, so we should expect variety among seeing-in. Dominic Lopes’s taxonomy of seeing-in is arguably the most thorough that is currently available. Lopes identifies five varieties of seeing-in. In this paper I identify a sixth: pseudo-actualism. This paper improves our current best taxonomy of seeing-in.

The subjective character of a given experience leaves open the question of its precise status. If it looks to a subject K as if there is an object of a kind F in front of him, the experience he is having could be veridical, or hallucinatory. Advocates of the Causal Theory of perception (whom I shall call.

When philosophers speak or write about hallucinations, they usually have perceptual (or ’true’) hallucinations in mind - that is, hallucinations which the subject mistakes for genuine perceptions and which have the same impact on his mental lives as the latter.1 One reason for this is the fact that philosophers tend to address the topic of hallucination, not for its own sake, but only in the context of some wider issues. Thus, when they are discussing hallucinations, they are primarily interested in (...) other topics, such a how - or whether - we are able to acquire knowledge about the external world, in which sense our mental states are directed at objects and properties, how best to account for what our experiences are subjectively like, which features suffice for something to count as a conscious experience, and so on. Especially the epistemic question, but also the connected issues in the philosophy of mind, lead them first of all to the phenomenon of genuine perception. For perceptions are precisely those mental episodes which point us to, and bring us into contact with, the world; and they also constitute the paradigm examples of conscious episodes with a distinctive phenomenal character. Hallucinations, on the other hand, do neither. Instead, they become relevant for the epistemic and related considerations only in so far as they give rise to sceptical scenarios and cast doubt on the common-sense (or naive) conception of the nature of perceptual experiences. And, in both cases, only those hallucinations matter which are indistinguishable from genuine perceptions with respect to their content and character.2 In the cognitive sciences (broadly understood as ranging from, say, neuroscience to developmental or evolutionary psychology), by contrast, hallucinations are much more prominent objects of study, and moreover objects of study in their own right. From the perspective of empirical investigations of the brain and mind - whether they utilise neuroimaging, observe behaviour, or examine verbal reports - hallucinations simply form one class of mental phenomena among many, all of which are ultimately in the same need of being studied and accounted for as part of our attempt to come to a full understanding of how our psychology works and is neurally realised.. (shrink)

One central fact about hallucinations is that they may be subjectively indistinguishable from perceptions. Indeed, it has been argued by M. G. F. Martin and others that the hallucinatory experiences concerned cannot — and need not — be characterised in any more positive general terms. This epistemic conception of hallucinations has been advocated as the best choice for proponents of experiential (or ‘na¨ıve realist’) disjunctivism — the view that perceptions and hallucinations differ essentially in their introspectible subjective characters. In this (...) chapater, I aim to formulate and defend an intentional alternative to experiential disjunctivism called experiential intentionalism. This view does not only enjoy some advantages over its rival, but also can hold on to the epistemic conception of perception-like hallucinations. First of all, I try to spell out in a bit more detail in which sense hallucinations may be subjectively indistinguishable from perceptions, and why this leads us to erroneously judge them to be perceptions (cf. sections I–III and VIII). Then, I raise three challenges each for experiential disjunctivism and its orthodox intentionalist counterparts (cf. sections IV and V), notably in respect of the need to explicate why a perception-like hallucination still makes the same judgements reasonable from the subject’s perspective as the corresponding perceptions. And, finally, I propose my alternative both to experiential disjunctivism and to orthodox intentionalism. Experiential intentionalism takes perceptions and perception-like hallucinations to share a common character partly to be spelled out in intentional — and, hence, normative — terms (cf. sections VI and VII). The central thought is that the hallucinations concerned are intentionally — and erroneously — presented to us as perceptual relations to the world. I aim to show that the resulting view can meet all six challenges (cf. sections VI–VIII). I end.. (shrink)

Finding disjunctivist versions of direct realism unexplanatory, Mark Johnston [(2004). Philosophical Studies, 120, 113–183] offers a non-disjunctive version of direct realism in its place and gives a defense of this view from the problem of hallucination. I will attempt to clarify the view that he presents and then argue that, once clarified, it either does not escape the problem of hallucination or does not look much like direct realism.

Recent debates between representational and relational theories of perceptual experience sometimes fail to clarify in what respect the two views differ. In this essay, I explain that the relational view rejects two related claims endorsed by most representationalists: the claim that perceptual experiences can be erroneous, and the claim that having the same representational content is what explains the indiscriminability of veridical perceptions and phenomenally matching illusions or hallucinations. I then show how the relational view can claim that errors associated (...) with perception should be explained in terms of false judgments, and develop a theory of illusions based on the idea that appearances are properties of objects in the surrounding environment. I provide an account of why appearances are sometimes misleading, and conclude by showing how the availability of this view undermines one of the most common ways of motivating representationalist theories of perception. (shrink)

Recent neural models clarify many properties of mental imagery as part of the process whereby bottom-up visual information is influenced by top-down expectations, and how these expectations control visual attention. Volitional signals can transform modulatory top-down signals into supra-threshold imagery. Visual hallucinations can occur when the normal control of these volitional signals is lost.

Philosophers of mind have recently sought to establish a theoret- ical use for nonconceptual content. Although there is disagreement about what nonconceptual content is supposed to be, this much is clear. A state with nonconceptual content is mental. Hence, while one may deny that refrigerators and messy rooms have conceptual capacities, their states, as physical and not mental, do not have nonconceptual content. A state with nonconceptual content is also intentional, which is to say that it represents a feature of (...) the world for a subject. It may be tempting to think of qualitative states as having nonconceptual content since they can be experienced by indi- viduals independently of their possession of the requisite concepts, e.g. someone could experience pains, itches or tingles without possessing the concept pain, itch or tingle. But on such a view, one would have to assume that qualitative states are representational since mental states cannot be candidates for nonconceptuality unless they have intentional properties.2. (shrink)

This volume will be an essential resource for anyone working in the central areas of philosophy, and the starting point for future research in this fascinating ...

Inspired by the writings of J. M. Hinton (1967a, 1967b, 1973), but ushered into the mainstream by Paul Snowdon (1980–1, 1990–1), John McDowell (1982, 1986), and M. G. F. Martin (2002, 2004, 2006), disjunctivism is currently discussed, advocated, and opposed in the philosophy of perception, the theory of knowledge, the theory of practical reason, and the philosophy of action. But what is disjunctivism?

Although it has been something of a fetish for philosophers to distinguish between hallucination and illusion, the enduring problems for philosophy of perception that both phenomena present are not essentially different. Hallucination, in its pure philosophical form, is just another example of the philosopher’s penchant for considering extreme and extremely idealized cases in order to understand the ordinary. The problem that has driven much philosophical thinking about perception is the problem of how to reconcile our evident direct perceptual contact with (...) objects and properties with the equally evident fact that there is no phenomenological signal separating error and truth. “The obscure object of hallucination” offers a subtle and plausible solution to this problem and one that solves the problem generally, not just in the special case of hallucination. Johnston’s objective is to offer a theory of perception that meets two constraints: (1) that it provide an explanation of the possibility of delusive and veridical sensings that are indistinguishable from the first-person perspective and (2) that it count as form of direct realism where this is taken to involve acquaintance with the objects of perception. Johnston uses the first constraint to rule out disjunctivism. The second constraint is used to rule out conjunctivism, which as Johnston uses the term, includes most of the widely adopted philosophical theories of perception. Johnston also develops his own sophisticated and interesting theory of perception. In what follows, I will discuss the relation of Johnston’s theory to conjunctivism, examine one of his anti-conjunctivist arguments and finally compare Johnston’s theory with some other versions of direct realism. These topics constitute a very incomplete selection of the important issues discussed in this rich and interesting paper. I will also not disagree, in any fundamental way, with any of the central theses of Johnston’s discussion.. (shrink)

Like dreaming, hallucination has been a formative trope for modern philosophy. The vivid, often tragic, breakdown in the mind’s apparent capacity to disclose reality has long served to support a paradoxical philosophical picture of sensory experience. This picture, which of late has shaped the paradigmatic empirical understanding the senses, displays sensory acts as already complete without the external world; complete in that the direct objects even of veridical sensory acts do not transcend what we could anyway hallucinate. Hallucination is thus (...) the mother of Representationalism, which insists that it is mental intermediaries that make other.. (shrink)

Michael Martin aims to affirm a certain pattern of first-person thinking by advocating disjunctivism, a theory of perceptual experience which combines naive realism with the epistemic conception of hallucination. In this paper I argue that we can affirm the pattern of thinking in question without the epistemic conception of hallucination. The first part of my paper explains the link that Martin draws between the first-person thinking and the epistemic conception of hallucination. The second part of my paper explains how we (...) can achieve Martin’s ambition without Martin’s theory. One resource that I enlist for this purpose is a naive-realist friendly conception of first-person access to experience. The metaphysical theory that I enlist is a form of naive realism that endorses an intentionalist or representationalist “common-factor” approach to veridical and hallucinatory experience. The third part of my paper briefly develops this theory. (shrink)

An overview of the philosophy and psychology of hallucination and its relevance to the philosophy of perception.

A perceptual experience of a given object seems to make the object itself present to the perceiver’s mind. Many philosophers have claimed that naïve realism (the view that to perceive is to stand in a primitive relation of acquaintance to the world) provides a better account of this phenomenological directness of perceptual experience than does the content view (the view that to perceive is to represent the world to be a certain way). But the naïve realist account of this phenomenology (...) has a conspicuous shortcoming: it explains the phenomenological directness of veridical perceptual experiences but not of hallucinations. Conversely, I maintain that a particular variety of the content view provides a unified account of the phenomenological directness of both veridical and hallucinatory experiences. If so, then contrary to what is often assumed, the phenomenological facts concerning perceptual experience are explained better by the content view than by naïve realism, and consequently, we have a compelling reason to prefer the content view to naïve realism. (shrink)

Cultural differences in the perception of geometric illusions. Science 139: 769- 71. Shepard, RN 1 99o. Mind sights. New York: Freeman & Co. ...

Stoffregen & Bardy (S&B) make the point that the statement “I am moving” made by subjects in a “swinging room” cannot be explained as an illusion of motion, and there is thus no perceptual illusion. In this they are correct. There is in fact motion, but of the environment. We argue that the subjects misinterpret this because the information to the visual system is ambiguous and also deceiving.

Tradition has it that, although we experience darkness, we can neither hear nor hallucinate silence. At most, we hear that it is silent, in virtue of lacking auditory experience. This cognitive view is at odds with our ordinary thought and talk. Yet it is not easy to vouchsafe the perception of silence: Sorensen‘s recent account entails the implausible claim that the permanently and profoundly deaf are perpetually hallucinating silence. To better defend the view that we can genuinely hear and hallucinate (...) silence, we must reject the austere picture of conscious experience which underpins the cognitive theory. According to that picture, conscious experience is a simple relation between subjects and objects. In the absence of an object, there is no relation, and so no experience. By enriching this picture, room can be found for the experience of silence. I explore this idea in two phases. First, I defend the thought that we can hear and hallucinate certain forms of silence, such as pauses, in virtue of experiencing contrastive sounds. Second, I draw on Moore‘s analysis of sensation to suggest that simply experiencing silence is a special form of objectless consciousness. I offer two ways of fleshing out this idea. According to the first, auditory experience possesses a temporal field within which the absence of sounds can be perceived. According to the second, purely Moorean account, it is our capacity to listen in the absence of sounds that underlies the phenomenon of experiencing silence. (shrink)

How should the Na¨ıve Realist who eschews representational percep- tual content account for illusions? Bill Brewer has recently proposed that illusions should be treated solely in terms of post-experiential misjudgement.

The psychological concept of illusion is defined as a process involving an interaction of logical and empirical considerations. Common usage suggests that an illusion is a discrepancy between one's awareness and some stimulus. Following preliminary definitions of classes of stimuli, five definitions of illusion are considered, based upon the possible discrepancies between awareness and a stimulus. It is found that each of these definitions fails to make important distinctions, even to the point of equating all illusory and perceptual phenomena. This (...) dilemma is resolved by redefining illusion without reference to truth or falsity, but relative to the functioning of a given perceptual system under different conditions. The definition accepted as best is 'a discrepancy between one's perceptions of an object or event observed under different conditions'. Conditions may differ in terms of stimulus exposure, stimulus context, or experiental context. The philosophical and psychological implications are discussed of accepting a definition of illusion not based on a discrepancy between awareness and a stimulus. (shrink)

Early formulations of disjunctivism about perception refused to give any positive account of the nature of hallucination, beyond the uncontroversial fact that they can in some sense seem to the same to the subject as veridical perceptions. Recently, some disjunctivists have attempt to account for hallucination in purely epistemic terms, by developing detailed account of what it is for a hallucinaton to be indiscriminable from a veridical perception. In this paper I argue that the prospects for purely epistemic treatments of (...) hallucinations are dim, and that this undermines the case for disjunctivism. (shrink)

In this paper, I describe and criticize M.G.F. Martin's version of disjunctivism, and his argument for it from premises about self-knowledge.

Defending a form of naïve realism about visual experiences is quite popular these days. Those naïve realists who I will be concerned with in this paper make a central claim about the subjective aspects of perceptual experiences. They argue that how it is with the perceiver subjectively when she sees worldly objects is literally determined by those objects. This way of thinking leads them to endorse a form of disjunctivism, according to which the fundamental psychological nature of seeings and hallucinations (...) is distinct. I will oppose their central claim by defending a version of the so-called ‘causal argument’, which dwells on ideas about causation and explanation in perception. The aim of this discussion is to highlight that the subjective aspects of perceptual experiences cannot be explained in naïve realist terms. Instead, it will be argued that one needs to appeal to a mental factor which does not involve worldly objects as constituents, and which is common to seeings and hallucinations. (shrink)

A comprehensive theory of the structure and cognitive function of the human imagination, and its relationship to perceptual experience, is developed, largely through a critique of the account propounded in Colin McGinn's Mindsight. McGinn eschews the highly deflationary (and unilluminating) views of imagination common amongst analytical philosophers, but fails to develop his own account satisfactorily because (owing to a scientifically outmoded understanding of visual perception) he draws an excessively sharp, qualitative distinction between imagination and perception (following Wittgenstein, Sartre, and others), (...) and because of his fatally flawed, empirically ungrounded conception of hallucination. In fact, however, an understanding of perception informed by modern visual science will enable us to unify our accounts of perception, mental imagery, dreaming, hallucination, creativity, and other aspects of imagination within a single coherent theoretical framework. (shrink)

Phenomenal character is determined by representational content, which both hallucinatory and veridical experiences can share. But in the case of veridical experience, unlike hallucination, the external objects of experience literally have the properties one is aware of in experience. The representationalist can accept the common factor assumption without having to introduce sensory intermediaries between the mind and the world, thus securing a form of direct realism.

Keith has just taken a hallucinogenic drug. A few minutes earlier, he was occupied with the beginning of H.H. Price's well-known book on perception. The combined effect of these activities is that Keith is now hallucinating a ripe tomato. This is not a de re hallucination. There is no particular tomato located elsewhere out of Keith's vision such that he is hallucinating that tomato as being before him. Keith is hallucinating a tomato without there being any particular tomato that he (...) is hallucinating. What is the representational content of Keith‟s experience? (shrink)

My purpose is to take a close look at the nature of visual content. I discuss the view that visual experiences have only existential contents, the view that visual experiences have either singular or gappy contents, and the view that visual experiences have multiple contents. I also consider a proposal about visual content inspired by Kaplan's well known theory of indexicals. I draw out some consequences of my discussion for the thesis of intentionalism with respect to the phenomenal character of (...) visual experience. (shrink)

Perhaps the greatest challenge to an existential phenomenological account of perception is that posed by the argument from illusions. Recent developments in research on the behaviour of subjects suffering from illusions together with some seminal ideas found in Merleau-Ponty''s writings enable us to develop and corroborate an account of the phenomenon of illusions, one, which unlike the empiricist account, does not undermine our conviction that in perception we reach the things themselves. The traditional argument from illusions derives its force from (...) an uncritical assumption that the process of experience takes place in time conceived as an infinite series of distinct moments. Once this assumption has been bracketed we are able to recognise the paradoxical truth that in the disillusion something can become that which it has always been and can cease to be that which it has never been. Furthermore, through a reflection on our experience of others overcoming their illusions, and on psychological evidence, we are able to show that there is nothing to suggest that this description of the disillusion is a description of a private or subjective event. (shrink)